Process for breaking petroleum emulsions



Patented June 13, 1944 Search Room PROCESS FOR BREAKING PETROLEUM EMULSIONS Melvin De Groote, University City, and Bernhard Keiser, Webster Groves, Mo., ,assignors to Petrolite Corporation, Ltd., Wilmington, Del., a

corporation of Delaware No Drawing. Application October 26, 1942, Serial No. 463,437

4 Claims.

This invention relates to the treatment of petroleum emulsions, and has for its main object to provide a novel process for resolving petroleum emulsions of the water-in-oil type that are commonly referred to as cut oil, roily oil, emulsified oil, etc., and which comprise fine droplets of naturally-occurring waters or brines dispersed in a more or less permanent state throughout the oil which constitutes the continuous phase of the emulsion.

Another object of our invention is to provide an economical and rapid process for separating emulsions which have been prepared under controlled conditions from mineral oil, such as crude oil and relatively soft waters or weak brines. Controlled emulsification and subsequent demulsification under the conditions just mentioned is of significant value in removing impurities, particularly inorganic salts from pipeline oil.

Briefly described, our invention consists in subjecting a petroleum emulsion of the water-in-oil type, to the action of a demulsifier comprising a derivative of the water soluble type of petroleum sulfonic acid, commonly known as green acids. Petroleum sulfonic acids are produced from a wide variety of petroleum distillates or petroleum fractions, and in some instances, they are produced from the crude petroleum itself. When produced from crude petroleum itself, it is customary to use crude oil of the naphthenic type, crude oil of the paraffin type, crude oil of the asphaltic type, and mixtures of said three different types of crude oil.

The art of refining crude petroleum or various fractions, using sulfuric acid of various strengths, as well as monohydrate and fuming acid, is a well-known procedure. In such conventional refiningprocedure, petroleum sulfonic acids have been produced as by-products. For instance, in removing the olefinic components, it has been common practice to use sulfuric acid so as to polymerize the oleflnes or convert them into sulfonic acids which are subsequently removed. Likewise, in the production of white oil, or highly refined lubricating oils, it has been customary to treat with fuming sulfuric acid, so as to eliminate certain undesirable components.

In recent years, certain mineral oil fractions have been treated with sulfuric acid with the primary object of producing petroleum sulfonic acids, and in such procedure the petroleum sulfonic acids represented the primary products of reaction, rather than concomitant by-products.

Petroleum sulfonic acid, regardless of whether derived as the principal product of reaction, or. 55

as a by-product, can be divided into two general products, to wit, green acid or acids and mahogany acid or acids. The green acids are characterized by being water-soluble or dispersible. In other words, they form either true solutions or sols. For purpose of convenience, they will be herein referred to as water-soluble, without any effort to indicate whether the solution is molecular or colloidal in nature. The green acids, as indicated by their name, frequently give an aqueous solution having a dark green or gray-green appearance. They generally appear as a component of the acid draw-off, and do not remain behind dissolved in the oil fraction which has been subjected to sulfuric acid treatment. The green acids are not soluble in oil, even when substantially anhydrous, and certainly are not solubl in oil when they contain as much as 15% of water. Similarly, their salts obtained by neutralizing the green acids with a strong solution of caustic soda, caustic potash, or ammonia, are not oil-soluble. For convenience of classification, the ammonium salt will be considered as an alkali salt.

In contradistinction to the hydrophile green acids, there occurs as in the manufacture of medicinal white oil, the oil-soluble type of the ma.- hogany acids. These mahogany acids are characterized by being soluble in oil, especially when anhydrous, and being soluble in oil, even if they contain some dissolved water. Some of the mahogany acids also show limited hydrophilic properties to the extent that either some water can be dissolved in the acids, or they, in turn, may dissolve to some extent in water. In some instances their salts, such as the sodium, ammonium, or potassium salt, will dissolve in water to give a colloidal sol. However, regardless of the presence of any hydrophilic properties whatsoever, they always have a characteristic hydrophobe property, as indicated by the fact that the substantially anhydrous form, for instance, their alkali salts containing 5-l2'% water, will dissolve in oil. This clearly distinguishes them from the green acids previously referred to, because the green acids in similar form containing the same amount of water, for example, will not dissolve in oil. The green acids, as such, are essentially hydrophilic and non-hydrophobic in character.

The utility of the mahogany acids in various arts has been enhanced by increasing their wator-solubility; for instance, converting the mahogany acids into hydroxy alkylamine salts. On the other hand, as far as we are aware, no valuable product of commerce has resulted from decreasing the water solubility of the mahogany acids by the addition of some oil-soluble basic amine, such as, for example, triamylamine. The triamylamine salts of mahogany acids, for example, are completely devoid of any solubility in water which the alkali salts may have exhibited and show, as would be expected, an increased solubility in hydrophobe solvents.

Green acids are hydrophile in character, as previously stated. Their hydrophile character has been increased by neutralization with materials such as triethanolamine and the like. Such green acid salts, having enhanced water solubility, as compared with the ordinary alkali salts, have found application in certain arts.

We have found that if green acids, 1. e., the oil-insoluble type, are neutralized with 2-amino- 2-methylpentanol-4, the resultant product has pronounced value as a demulsifler for oil field emulsions of the water-in-oil type, either when used alone, or when used in conjunction with other compatible and well-known demulsifying agents.

The 2-amino-2-methylpentanol-4 may be manufactured in various ways. One of the most suitable methods is to convert acetone or some other equivalent reactant into mesityl oxide. Mesityl oxide can then be reacted with ammonia to give diacetonamine. Diacetonamine can be hydrogenated readily to yield 2-amino-2--methylpentanoli. See Richters Organic Chemistry, (Allott), Aliphatic Series, 1934 edition, page 274. See also Beilstein, volume 4, edition 4, page 296 (System #354.)

The manufacture of the new chemical compound employed as the demulsifier in our process, contemplates nothing more or less than neutralizing the selected petroleum sulfonic acid, with 2-amino-2-methylpentanol-4 until neutral to litmus indicator or some other suitable indicator. For purposes of convenience, we prefer that the selected petroleum sulfonic acid contain not over 15% of water. It is understood, of course, that conventional procedure employing double decomposition instead of direct neutralization, can be employed in the manufacture of our new material or composition of matter.

It may be well to point out that hydrophile non-hydrophobe petroleum sulfonic acid or acids of the green acid type vary somewhat; for instance, the molecular weight may vary within the range of 350-500, or thereabouts. Naturally, these petroleum sulfonic acids may carry some polymerized olefines, free hydrocarbons, or the like, or may even carry a bit of naphthenic acids which represent carboxylated non-sulfonated petroleum acids. As previously stated, these ma terials are well-known commercial products and are available in the open market, either in the form of the acid itself, or in the form of a salt.

Although it is believed, in view of what has been said previously, that no further descrip tion is required in regard to the manufacture of the new compounds herein contemplated, and the following examples are added purely by way of illustration:

Example 1 Green acids are obtained from Gulf Coast lubricating oil distillate having an S. U. viscosity at 150 F. of about 400 seconds. The procedure employed in obtaining such green acids is, that described in U. S. Patent No. 2,188,770, dated January 30, 1940, to Robertson. The material so obtained contains considerable moisture and is preferably dehydrated to the point where the moisture content is not over 15%. The sulfonic acid is then neutralized to litmus indicator with 2-amino-2-methylpentanol-4.

Example 2 The same procedure is followed as in Example l, but instead, the green acids are obtained from Gulf Coast transformer oil extract in the manner described in U. S. Patent No. 2,203,443, dated June 4, 1940, to Ross and Mitchell.

Example 3 The same procedure is followed as in Example 2, except that California 65 Saybolt viscosity .hdeleanu extract is employed instead of Gulf Coast transformer Edeleanu extract employed in Example 2.

Example 4 The same procedure is followed as in Example 1, except that the product is made from a Gulf Coast naphthene type crude, preferably of the kind which has little or no low boiling fraction, 1. e., the kind which, on a straight run distillation, gives little or no gasoline.

Conventional demulsifying agents employed in the treatment of oil field emulsions are used as such, or after dilution with any suitable solvent, such as water, petroleum hydrocarbons, such as gasoline, kerosene, stove oil, a coal tar product, such as benzene, toluene, xylene, tar acid 011, cresol, anthl'acene oil, etc. Alcohols, particulariy aliphatic alcohols, such as methyl alcohol, ethyl alcohol, denatured alcohol, propyl alcohol, butyl alcohol, hexyi alcohol, octyl alcohol, etc.. may be employed as diluents. Miscellaneous solvents, such as pine oil, carbon tetrachloride, sulfur dioxide extract obtained in the refining of petroleum, etc., may be employed as diluents. Similarly, the material or materials employed as the demulsifying agent of our process, may be admixed with one or more of the solvents customarily used in connection with conventional demulsifying agents. Moreover, said material or materials may be used alone, or in admixture with other suitable well-known classes of demulsifying agents.

it is well known that conventional demulsifying agents may be used in a water-soluble form, or in an oil-soluble form, or in a form exhibiting both oil and water solubility. Sometimes they may be used in a form which exhibits relatively limited oil solubility. However, since such reagents are sometimes used in a ratio of l to 10,000, or 1 to 20,000, or even 1 to 30,000, such an apparent insolubility in oil and water is not significant, because said reagents undoubtedly have solubility within the concentration employed. This same fact is true in regard to the material or materials employed as the demulsifying agent of our process.

We desire to point out that the superiority of the reagent or demulsifying agent contemplated in our process is based upon its ability to treat certain emulsions more advantageously and at a somewhat lower cost than is possible with other available demulsifiers, or conventional mixtures thereof. It is believed that the particular demulsifying agent or treating agent herein described will find comparatively limited application, so far as the majority of oil field emulsions are concerned; but we have found that such a demulsifying agent has commercial value, as it will economically break or resolve oil field emulsions in a number of cases which cannot be treated as easily or at so low a cost with the demulsifying agents heretofore available.

In practising our process, a treating agent or demulsifying agent of the kind above described is brought into contact with or caused to act upon the emulsion to be treated, in any of the various ways, or by any of the various apparatus now generally used to resolve or break petroleum emulsions with a chemical reagent, the above procedure being used either alone, or in combination with other demulsifying procedure, such as the electrical dehydration process.

The demulsifier contemplated may be employed in connection with what is commonly known as down-the-hole procedure, i. e., bringing the demulsifier in contact with the fluids of the well at the bottom of the well, or at some point prior to their emergence. This particular type of application is decidedly feasible when the demulsifier is used in connection with acidification of calcareous oil-bearing strata, especially if suspended in or dissolved in the acid employed for acidification. The new material or compound herein described forms the subjectmatter of our divisional application Serial No. 500,719, filed August 30, 1943.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A process for resolving petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a de-' mulsifier comprising the 2-amino-2-methylpentanol-4 salt of water-soluble, non-hydrophobe petroleum sulfonic acids of the green acid type.

2. -A process for resolving petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifler comprising the 2-amino-2-methyl-pentanol-gi salt of water-soluble, non-hydrophobe petroleum sulfonic acids of the green acid type; said green acid being obtained from a naphthene-type crude.

3. A process for resolving petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier comprising the 2-amino-2-methyl-pentanol-4 salt of water-soluble, non-hydrophobe petroleum sulionic acids of the green acid type: said green acid being obtained from a paraflin type crude.

4. A process for resolving petroleum emulsions of the water-in-oil type, characterized by subjecting the emulsion to the action of a demulsifier comprising the 2-amino-2-methyl-pentanol-4 salt of water-soluble, non-hydrophobe petroleum sulfonic acids of the green acid type; said green acid being obtained from an asphaltic type crude.

MELVIN DE GROOTE. BERNHARD KEISER. 

